LePore, Kate , Elkin, Galina , Thanavala, Yasmin , Mason, Hugh .
TMV vector-based expression of a mucosal targeting hepatitis B vaccine in Nicotiana benthamiana leaf and its immunogenicity in mice.
Hepatitis B small surface antigen (HBsAg) produced in plant systems has been shown to be orally immunogenic in mice and humans. However, resulting antibody titers from these experiments suggest delivery of the plant-derived material via the oral route stimulates a limited immune response. Current strategies to improve the immunogenicity of orally delivered, plant-derived HBsAg include the direct presentation of antigen to the gut-associated lymphoid tissue (GALT) via mucosal targeting fusion proteins. Invasin is a Yersinia pseudotuberculosis outer membrane protein that binds to Î²-1 integrins on Peyer’s patches (GALT) located on the epithelium of the small intestine. We hypothesize that a HBsAg-invasin fusion will bind to Peyer’s patches when delivered orally, and thus will elicit a more potent immune response than the unmodified antigen.
The C-terminal 197 residues of invasin were codon optimized for expression in dicotyledonous plant systems synthesized de novo. A fusion with HBsAg was then generated and transient protein expression characterized in small-scale. Sucrose density gradient confirmed virus-like particle (VLP) formation, and surface plasmon resonance (Biacore technology) was employed to confirm the presence of invasin on the surface of the fusion protein VLPs, a necessity for mucosal targeting. A novel Agrobacterium delivered TMV-based viral replicating system (magnICON) was then used to generate large quantities of both the fused and unmodified antigens in Nicotiana benthamiana leaf. Partially purified VLPs were administered to mice via oral gavage to test the adjuvant effect of the invasin fusion. Data from protein expression analyses, Biacore experimentation and oral immunogenicity studies will be presented and discussed.
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1 - The Biodesign Institute at Arizona State University, Center for Infectious Diseases and Vaccinology, PO Box 875401, Tempe, AZ, 85287, USA
2 - Roswell Park Cancer Institute, Department of Molecular Immunology
3 - The Biodesign Institute at Arizona State University, Center for Infectious Diseases and Vaccinology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM